CVE-2026-59847 Libssh: libssh: integrity downgrade via openssl aes-gcm tag verification
An in-path attacker can modify SSH traffic without detection due to flawed AES-GCM integrity checks in the OpenSSL backend of libssh.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-59847?
CVE-2026-59847 is a medium-severity vulnerability in Redhat Enterprise Linux, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A flaw was found in libssh. Incorrect AES-GCM finalization checks in builds using the OpenSSL backend can effectively remove integrity protection, allowing an in-path attacker to modify plaintext on the wire without detection.
Which versions are affected by CVE-2026-59847?
It affects 3 products.
Products include Libssh Libssh, Redhat Enterprise Linux, Redhat Hardened Images.
How do I fix CVE-2026-59847?
Apply the vendor's patch.
Is CVE-2026-59847 being exploited?
There is no known exploitation of CVE-2026-59847 in the wild and no public exploit code.
Other vulnerabilities in Redhat Enterprise Linux
- CVE-2026-59851 Libssh: libssh: authentication bypass via missing gssapi principal check
- CVE-2025-5987 Libssh: invalid return code for chacha20 poly1305 with openssl backend
- CVE-2025-14821 Libssh: libssh: insecure default configuration leads to local man-in-the-middle attacks on windows
- CVE-2012-4560 Memory corruption in n/a
- CVE-2012-4562 Integer overflow in n/a
Sources
Also known as AZL-93246, BELL-CVE-2026-59847, CLSA-2026-1785837599, DEBIAN-CVE-2026-59847, ECHO-c402-a16c-cfd9, GHSA-mq2j-7vq4-77m8 and 2 more.